Precision casting is currently motivated by high demand especially for castings for the aerospace, automotive and gas turbine industries. High demands on precision of this parts pressure foundries to search for the new tools which can help them to improve the production. One of these tools is the numerical simulation of injection process, whereas such software especially for investment casting wax injection, process does not exist yet and for this case must be the existing software, for alloys or plastic, modified. This paper focuses on the use of numerical simulations to predict the behavior of injected models of gas turbine blades segments. The properties of wax mixtures, which were imported into the Cadmould simulation software as a material model, were found. The results of the simulations were verified using the results of 3D scanning measurements of wax models. As a supporting technology for verifying the results was used the Infrared Thermography.